//
// --------------------------------------------------------------------------
//  Gurux Ltd
//
//
//
// Filename:        $HeadURL$
//
// Version:         $Revision$,
//                  $Date$
//                  $Author$
//
// Copyright (c) Gurux Ltd
//
//---------------------------------------------------------------------------
//
//  DESCRIPTION
//
// This file is a part of Gurux Device Framework.
//
// Gurux Device Framework is Open Source software; you can redistribute it
// and/or modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; version 2 of the License.
// Gurux Device Framework is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU General Public License for more details.
//
// This code is licensed under the GNU General Public License v2.
// Full text may be retrieved at http://www.gnu.org/licenses/gpl-2.0.txt
//---------------------------------------------------------------------------

#include "../include/gxignore.h"
#ifndef DLMS_IGNORE_AES
#include <string.h> // CBC mode, for memset
#include <stdint.h>
#include "../include/gxaes.h"

#if defined(USE_AVR) || defined(ARDUINO_ARCH_AVR)
//If AVR is used.
#include <avr/pgmspace.h>
#endif //#if defined(USE_AVR) || defined(ARDUINO_ARCH_AVR)

#define Nb 4
#define BLOCKLEN 16 //Block length in bytes AES is 128b block only

#if defined(AES256) && (AES256 == 1)
#define Nk 8
#define KEYLEN 32
#define Nr 14
#define keyExpSize 240
#elif defined(AES192) && (AES192 == 1)
#define Nk 6
#define KEYLEN 24
#define Nr 12
#define keyExpSize 208
#else
#define Nk 4        // The number of 32 bit words in a key.
#define KEYLEN 16   // Key length in bytes
#define Nr 10       // The number of rounds in AES Cipher.
#define keyExpSize 176
#endif

#ifndef MULTIPLY_AS_A_FUNCTION
#define MULTIPLY_AS_A_FUNCTION 0
#endif

// state - array holding the intermediate results during decryption.
typedef unsigned char state_t[4][4];
static state_t* state;

// The array that stores the round keys.
static unsigned char RoundKey[keyExpSize];

// The Key input to the AES Program
static const unsigned char* Key;

#if defined(CBC) && CBC
// Initial Vector used only for CBC mode
static unsigned char* Iv;
#endif

#ifndef USE_PROGMEM
    static const unsigned char __SBOX[256] = {
#else
    static const unsigned char __SBOX[256] PROGMEM = {
#endif //#if defined(_WIN32) || defined(_WIN64)
    //0     1    2      3     4    5     6     7      8    9     A      B    C     D     E     F
    0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76,
    0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
    0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
    0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,
    0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
    0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
    0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,
    0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
    0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
    0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,
    0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
    0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
    0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,
    0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
    0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
    0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16 };

#ifndef USE_PROGMEM
    static const unsigned char __RS_BOX[256] = {
    #else
    static const unsigned char __RS_BOX[256] PROGMEM = {
#endif //#if defined(_WIN32) || defined(_WIN64)
    0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb,
    0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb,
    0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e,
    0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25,
    0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92,
    0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84,
    0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06,
    0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b,
    0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73,
    0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e,
    0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b,
    0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4,
    0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f,
    0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef,
    0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61,
    0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d };

// The round constant word array, Rcon[i], contains the values given by
// x to th e power (i-1) being powers of x (x is denoted as {02}) in the field GF(2^8)
#ifndef USE_PROGMEM
    static const unsigned char __R_CON[11] = {
#else
static const unsigned char __R_CON[11] PROGMEM = {
#endif //#if defined(_WIN32) || defined(_WIN64)
    0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36 };

#if 0
#ifndef USE_PROGMEM
static const unsigned char __R_CON[256] = {
#else
static const unsigned char __R_CON[256] PROGMEM = {
#endif //#if defined(_WIN32) || defined(_WIN64)
    0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a,
    0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39,
    0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a,
    0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8,
    0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef,
    0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc,
    0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b,
    0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3,
    0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94,
    0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20,
    0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35,
    0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f,
    0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04,
    0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63,
    0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd,
    0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d };
#endif

static unsigned char getSBoxValue(unsigned char offset)
{
#ifdef ARDUINO_ARCH_AVR
    //If Arduino is used data is read from flash like this.
    return pgm_read_byte_near(__SBOX + offset);
#else
    return __SBOX[offset];
#endif //ARDUINO_ARCH_AVR
}

static unsigned char getSBoxInvert(unsigned char offset)
{
#ifdef ARDUINO_ARCH_AVR
    //If Arduino is used data is read from flash like this.
    return pgm_read_byte_near(__RS_BOX + offset);
#else
    return __RS_BOX[offset];
#endif //ARDUINO_ARCH_AVR
}

static unsigned char getRCon(unsigned char offset)
{
#ifdef ARDUINO_ARCH_AVR
    //If Arduino is used data is read from flash like this.
    return pgm_read_byte_near(__R_CON + offset);
#else
    return __R_CON[offset];
#endif //ARDUINO_ARCH_AVR
}

// This function produces Nb(Nr+1) round keys. The round keys are used in each round to decrypt the states.
static void KeyExpansion(void)
{
    unsigned char k;
    uint32_t i;
    // Used for the column/row operations
    unsigned char tempa[4];

    // The first round key is the key itself.
    for (i = 0; i < Nk; ++i)
    {
        RoundKey[(i * 4) + 0] = Key[(i * 4) + 0];
        RoundKey[(i * 4) + 1] = Key[(i * 4) + 1];
        RoundKey[(i * 4) + 2] = Key[(i * 4) + 2];
        RoundKey[(i * 4) + 3] = Key[(i * 4) + 3];
    }

    // All other round keys are found from the previous round keys.
    //i == Nk
    for (; i < Nb * (Nr + 1); ++i)
    {
        {
            tempa[0] = RoundKey[(i - 1) * 4 + 0];
            tempa[1] = RoundKey[(i - 1) * 4 + 1];
            tempa[2] = RoundKey[(i - 1) * 4 + 2];
            tempa[3] = RoundKey[(i - 1) * 4 + 3];
        }

        if (i % Nk == 0)
        {
            // This function shifts the 4 bytes in a word to the left once.
            // [a0,a1,a2,a3] becomes [a1,a2,a3,a0]

            // Function RotWord()
            {
                k = tempa[0];
                tempa[0] = tempa[1];
                tempa[1] = tempa[2];
                tempa[2] = tempa[3];
                tempa[3] = k;
            }

            // SubWord() is a function that takes a four-byte input word and
            // applies the S-box to each of the four bytes to produce an output word.

            // Function Subword()
            {
                tempa[0] = getSBoxValue(tempa[0]);
                tempa[1] = getSBoxValue(tempa[1]);
                tempa[2] = getSBoxValue(tempa[2]);
                tempa[3] = getSBoxValue(tempa[3]);
            }

            tempa[0] = (unsigned char)(tempa[0] ^ getRCon((unsigned char)(i / Nk)));
        }
#if defined(AES256) && (AES256 == 1)
        if (i % Nk == 4)
        {
            // Function Subword()
            {
                tempa[0] = getSBoxValue(tempa[0]);
                tempa[1] = getSBoxValue(tempa[1]);
                tempa[2] = getSBoxValue(tempa[2]);
                tempa[3] = getSBoxValue(tempa[3]);
            }
        }
#endif
        RoundKey[i * 4 + 0] = RoundKey[(i - Nk) * 4 + 0] ^ tempa[0];
        RoundKey[i * 4 + 1] = RoundKey[(i - Nk) * 4 + 1] ^ tempa[1];
        RoundKey[i * 4 + 2] = RoundKey[(i - Nk) * 4 + 2] ^ tempa[2];
        RoundKey[i * 4 + 3] = RoundKey[(i - Nk) * 4 + 3] ^ tempa[3];
    }
}

// This function adds the round key to state.
// The round key is added to the state by an XOR function.
static void AddRoundKey(unsigned char round)
{
    unsigned char i, j;
    for (i = 0; i < 4; ++i)
    {
        for (j = 0; j < 4; ++j)
        {
            (*state)[i][j] ^= RoundKey[round * Nb * 4 + i * Nb + j];
        }
    }
}

// The SubBytes Function Substitutes the values in the
// state matrix with values in an S-box.
static void SubBytes(void)
{
    unsigned char i, j;
    for (i = 0; i < 4; ++i)
    {
        for (j = 0; j < 4; ++j)
        {
            (*state)[j][i] = getSBoxValue((*state)[j][i]);
        }
    }
}

// The ShiftRows() function shifts the rows in the state to the left.
// Each row is shifted with different offset.
// Offset = Row number. So the first row is not shifted.
static void ShiftRows(void)
{
    unsigned char temp;

    // Rotate first row 1 columns to left
    temp = (*state)[0][1];
    (*state)[0][1] = (*state)[1][1];
    (*state)[1][1] = (*state)[2][1];
    (*state)[2][1] = (*state)[3][1];
    (*state)[3][1] = temp;

    // Rotate second row 2 columns to left
    temp = (*state)[0][2];
    (*state)[0][2] = (*state)[2][2];
    (*state)[2][2] = temp;

    temp = (*state)[1][2];
    (*state)[1][2] = (*state)[3][2];
    (*state)[3][2] = temp;

    // Rotate third row 3 columns to left
    temp = (*state)[0][3];
    (*state)[0][3] = (*state)[3][3];
    (*state)[3][3] = (*state)[2][3];
    (*state)[2][3] = (*state)[1][3];
    (*state)[1][3] = temp;
}

static unsigned char xtime(unsigned char x)
{
    return (unsigned char)((x << 1) ^ (((x >> 7) & 1) * 0x1b));
}

// MixColumns function mixes the columns of the state matrix
static void MixColumns(void)
{
    unsigned char i;
    unsigned char Tmp, Tm, t;
    for (i = 0; i < 4; ++i)
    {
        t = (*state)[i][0];
        Tmp = (*state)[i][0] ^ (*state)[i][1] ^ (*state)[i][2] ^ (*state)[i][3];
        Tm = (*state)[i][0] ^ (*state)[i][1]; Tm = xtime(Tm);  (*state)[i][0] ^= Tm ^ Tmp;
        Tm = (*state)[i][1] ^ (*state)[i][2]; Tm = xtime(Tm);  (*state)[i][1] ^= Tm ^ Tmp;
        Tm = (*state)[i][2] ^ (*state)[i][3]; Tm = xtime(Tm);  (*state)[i][2] ^= Tm ^ Tmp;
        Tm = (*state)[i][3] ^ t;              Tm = xtime(Tm);  (*state)[i][3] ^= Tm ^ Tmp;
    }
}

// Multiply is used to multiply numbers in the field GF(2^8)
#if MULTIPLY_AS_A_FUNCTION
static unsigned char Multiply(unsigned char x, unsigned char y)
{
    return (((y & 1) * x) ^
        ((y >> 1 & 1) * xtime(x)) ^
        ((y >> 2 & 1) * xtime(xtime(x))) ^
        ((y >> 3 & 1) * xtime(xtime(xtime(x)))) ^
        ((y >> 4 & 1) * xtime(xtime(xtime(xtime(x))))));
}
#else
#define Multiply(x, y)                                \
      (  ((y & 1) * x) ^                              \
      ((y>>1 & 1) * xtime(x)) ^                       \
      ((y>>2 & 1) * xtime(xtime(x))) ^                \
      ((y>>3 & 1) * xtime(xtime(xtime(x)))) ^         \
      ((y>>4 & 1) * xtime(xtime(xtime(xtime(x))))))   \

#endif

// MixColumns function mixes the columns of the state matrix.
// The method used to multiply may be difficult to understand for the inexperienced.
// Please use the references to gain more information.
static void InvMixColumns(void)
{
    int i;
    unsigned char a, b, c, d;
    for (i = 0; i < 4; ++i)
    {
        a = (*state)[i][0];
        b = (*state)[i][1];
        c = (*state)[i][2];
        d = (*state)[i][3];

        (*state)[i][0] = Multiply(a, 0x0e) ^ Multiply(b, 0x0b) ^ Multiply(c, 0x0d) ^ Multiply(d, 0x09);
        (*state)[i][1] = Multiply(a, 0x09) ^ Multiply(b, 0x0e) ^ Multiply(c, 0x0b) ^ Multiply(d, 0x0d);
        (*state)[i][2] = Multiply(a, 0x0d) ^ Multiply(b, 0x09) ^ Multiply(c, 0x0e) ^ Multiply(d, 0x0b);
        (*state)[i][3] = Multiply(a, 0x0b) ^ Multiply(b, 0x0d) ^ Multiply(c, 0x09) ^ Multiply(d, 0x0e);
    }
}


// The SubBytes Function Substitutes the values in the
// state matrix with values in an S-box.
static void InvSubBytes(void)
{
    unsigned char i, j;
    for (i = 0; i < 4; ++i)
    {
        for (j = 0; j < 4; ++j)
        {
            (*state)[j][i] = getSBoxInvert((*state)[j][i]);
        }
    }
}

static void InvShiftRows(void)
{
    unsigned char temp;

    // Rotate first row 1 columns to right
    temp = (*state)[3][1];
    (*state)[3][1] = (*state)[2][1];
    (*state)[2][1] = (*state)[1][1];
    (*state)[1][1] = (*state)[0][1];
    (*state)[0][1] = temp;

    // Rotate second row 2 columns to right
    temp = (*state)[0][2];
    (*state)[0][2] = (*state)[2][2];
    (*state)[2][2] = temp;

    temp = (*state)[1][2];
    (*state)[1][2] = (*state)[3][2];
    (*state)[3][2] = temp;

    // Rotate third row 3 columns to right
    temp = (*state)[0][3];
    (*state)[0][3] = (*state)[1][3];
    (*state)[1][3] = (*state)[2][3];
    (*state)[2][3] = (*state)[3][3];
    (*state)[3][3] = temp;
}


// Cipher is the main function that encrypts the PlainText.
static void Cipher(void)
{
    unsigned char round = 0;

    // Add the First round key to the state before starting the rounds.
    AddRoundKey(0);

    // There will be Nr rounds.
    // The first Nr-1 rounds are identical.
    // These Nr-1 rounds are executed in the loop below.
    for (round = 1; round < Nr; ++round)
    {
        SubBytes();
        ShiftRows();
        MixColumns();
        AddRoundKey(round);
    }

    // The last round is given below.
    // The MixColumns function is not here in the last round.
    SubBytes();
    ShiftRows();
    AddRoundKey(Nr);
}

static void InvCipher(void)
{
    unsigned char round = 0;

    // Add the First round key to the state before starting the rounds.
    AddRoundKey(Nr);

    // There will be Nr rounds.
    // The first Nr-1 rounds are identical.
    // These Nr-1 rounds are executed in the loop below.
    for (round = (Nr - 1); round > 0; --round)
    {
        InvShiftRows();
        InvSubBytes();
        AddRoundKey(round);
        InvMixColumns();
    }

    // The last round is given below.
    // The MixColumns function is not here in the last round.
    InvShiftRows();
    InvSubBytes();
    AddRoundKey(0);
}


/*****************************************************************************/
/* Public functions:                                                         */
/*****************************************************************************/
#if defined(ECB) && (ECB == 1)

void gxaes_ecb_encrypt(const unsigned char* input, const unsigned char* key, unsigned char* output, const size_t length)
{
    // Copy input to output, and work in-memory on output
    memcpy(output, input, length);
    state = (state_t*)output;

    Key = key;
    KeyExpansion();

    // The next function call encrypts the PlainText with the Key using AES algorithm.
    Cipher();
}

void gxaes_ecb_decrypt(const unsigned char* input, const unsigned char* key, unsigned char *output, const size_t length)
{
    // Copy input to output, and work in-memory on output
    memcpy(output, input, length);
    state = (state_t*)output;

    // The KeyExpansion routine must be called before encryption.
    Key = key;
    KeyExpansion();

    InvCipher();
}


#endif // #if defined(ECB) && (ECB == 1)

#if defined(CBC) && (CBC == 1)

static void XorWithIv(unsigned char* buf)
{
    unsigned char i;
    for (i = 0; i < BLOCKLEN; ++i) //WAS for(i = 0; i < KEYLEN; ++i) but the block in AES is always 128bit so 16 bytes!
    {
        buf[i] ^= Iv[i];
    }
}

void gxaes_cbc_encrypt(unsigned char* output, unsigned char* input, uint32_t length, const unsigned char* key, const unsigned char* iv)
{
    uintptr_t i;
    unsigned char extra = length % BLOCKLEN; /* Remaining bytes in the last non-full block */

                                       // Skip the key expansion if key is passed as 0
    if (0 != key)
    {
        Key = key;
        KeyExpansion();
    }

    if (iv != 0)
    {
        Iv = (unsigned char*)iv;
    }

    for (i = 0; i < length; i += BLOCKLEN)
    {
        XorWithIv(input);
        memcpy(output, input, BLOCKLEN);
        state = (state_t*)output;
        Cipher();
        Iv = output;
        input += BLOCKLEN;
        output += BLOCKLEN;
        //printf("Step %d - %d", i/16, i);
    }

    if (extra)
    {
        memcpy(output, input, extra);
        state = (state_t*)output;
        Cipher();
    }
}

void gxaes_cbc_decrypt(unsigned char* output, unsigned char* input, uint32_t length, const unsigned char* key, const unsigned char* iv)
{
    uintptr_t i;
    unsigned char extra = length % BLOCKLEN; /* Remaining bytes in the last non-full block */

                                       // Skip the key expansion if key is passed as 0
    if (0 != key)
    {
        Key = key;
        KeyExpansion();
    }

    // If iv is passed as 0, we continue to encrypt without re-setting the Iv
    if (iv != 0)
    {
        Iv = (unsigned char*)iv;
    }

    for (i = 0; i < length; i += BLOCKLEN)
    {
        memcpy(output, input, BLOCKLEN);
        state = (state_t*)output;
        InvCipher();
        XorWithIv(output);
        Iv = input;
        input += BLOCKLEN;
        output += BLOCKLEN;
    }

    if (extra)
    {
        memcpy(output, input, extra);
        state = (state_t*)output;
        InvCipher();
    }
}

#endif // #if defined(CBC) && (CBC == 1)

#endif //DLMS_IGNORE_AES
